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US 7,252,986 B2Granted
Process for the biodegradation of hydrocarbons and ethers in subsurface soil by introduction of a solid oxygen source by hydraulic fracturing
AssigneeU. S. Environmental Protection Agency
InventorsWendy Jo Davis-Hoover, Stephen J. Vesper
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Abstract
A bioremediation of subsurface soil formations contaminated with hazardous wastes is achieved by hydraulic fracturing of the subsurface soil formation with simultaneous introduction of sodium percarbonate coated with polyvinylidene chloride as a solid oxygen source (SOS) for establishing colonies of the biodegrading bacteria within the fractures of the soil formation.
Claims11
A process for biodegradation of hazardous hydrocarbon and/or ether wastes present in subsurface soil, said process comprising:
- admixing a proppant, sodium percarbonate coated with polyvinylidine chloride, and water to form a slurry;
- injecting the slurry into the subsurface soil at a hydraulic pressure sufficient to form fractures in the subsurface soil, the proppant serving to hold open the fractures;
- and
- establishing colonies of bacteria within the fractures, the bacteria having the capability of digesting and degrading the contaminants and the encapsulated sodium percarbonate serving as a solid oxygen source for supplying oxygen to the bacteria;
- and
- injecting additional oxygen and/or solid oxygen source into the subsurface soil with an interval of at least ten months between injections.
3 more elements
Dependencies are inferred from the claim text.